“Doors and sardines — that’s what it’s all about,” director Lloyd Dallas (Chris Kayser) tells his cast of fifth-rate actors as they struggle through their dress rehearsal for a dim little British sex farce. Doors, as in the seven doors on the two-story set, all of which must be entered, exited and slammed with the impeccable timing that bedroom farce demands, which his cast seems utterly incapable of. And sardines, which start out on a plate as a housekeeper’s snack and end up all over the set, establishing what is surely a record for the use of small rubber prop fish by Atlanta’s Georgia Shakespeare.

“Noises Off,” the achingly funny comedy that’s playing at Georgia Shakespeare’s home theater at Oglethorpe University through August 14, is Michael Frayn’s 1982 metafarce: a farce about a farce. The story goes that Frayn was standing backstage watching a performance of “Chinamen,” a farce he had written previously, and had the eureka moment that the play was even funnier when viewed from the wings. So he wrote the fiendishly complicated “Noises Off” (a theatrical term for sounds that originate offstage), which takes place both onstage and backstage on Kat Conley’s wonderful rotating set.

Act 2 is the comic high point, one month into the disastrous run of “Nothing On.” Now we are backstage, as the cast make their entrances and exits and wait for cues. A number of intercast affairs and betrayals, goosed by a generous helping of nitwittedness, leads to escalating squabbling among the actors, some of whom are trying to hurt one another while hitting their marks. (The script for Act 2 is written in two columns, as both plays are performed simultaneously on both sides of the set.)

Director Richard Garner sets loose a dizzying choreography of backstage chaos as the cast juggles, sometimes literally, a bottle of whiskey, a cactus plant, an ax and several bouquets of flowers. At one level it’s slapstick’s greatest hits (think the Three Stooges or Wile E. Coyote); at another it’s practically a ballet. In retrospect, it’s actually rather touching, how these truly bad actors in a truly bad play work so hard to fulfill that oldest of show biz adages, that the show must go on.

By Act 3, “Nothing On” is near the end of its run, and it has gotten worse with age. Now we watch the play as the audience sees it, as an escalating series of missed cues and other mishaps, Murphy’s Law at its peak, forcing the actors to improvise their way out of the bedlam. And the fun continues even after the play is over, as Georgia Shakespeare stalwart Kayser gets one of the better curtain calls; be sure not to miss his final bow.